Making the Diagnosis
When the heart beats faster than normal, it's called tachycardia. Atrial fibrillation is one type of tachycardia. If too many impulses are allowed through to the ventricles, your heart rate may be greater than 100 beats per minute. Conversely, if not many impulses are allowed through, your heart rate may, in fact, be slow.
The stethoscope is still a valuable instrument when it comes to detecting arrhythmias like atrial fibrillation, but there are modern tests that can pinpoint the problem. The electrocardiogram (ECG) prints a graph of the heart's electrical activity using small electrodes taped to the chest. The pattern on these graphs reveals the type of arrhythmia and can help the doctor diagnose atrial fibrillation. Since the arrhythmia might not occur at the hospital, there are portable ECGs that you can bring home. Some are constantly turned on over a specified period of time (these are called Holter Monitors), while others are turned on by you when you feel palpitations (these are called Event Monitors). Some of these devices can download the heart signal data over the phone line.
Electrophysiologic study (EPS) is a more elaborate test. Thin tubes are inserted into a blood vessel in the leg and guided up to the heart. They hold electrodes that can find the heart tissue that may be over-riding the signals from the sinus node.
Your doctor may also order blood tests to determine if another condition (e.g., thyroid imbalances) is associated with your atrial fibrillation.